Sod harvesting machines have long existed for harvesting sod and forming it into rolls, slabs or the like so that such cut sod may be laid in an appropriate location to produce a lawn. However no commercially successful machines have ever been available to lay the cut sod. Instead the laying operation has always been labour intensive and back breaking. The heavy rolls or slabs of sod are lifted, commonly by hand, to the desired location and are then unrolled and laid as closely as possible against the edge of the previously laid sod. Frequently the sod after being laid must be pushed sideways over the ground to fit tightly against the edge of the adjoining sod. The operation is time consuming and arduous.
There are numerous difficulties involved in laying sod by machine. Sod is an extremely difficult material with which to work, because it is heavy (due to the layer of earth attached to the roots of the grass) and yet it has very little tensile strength. The tensile strength of the sod can also vary greatly from one sample to another depending on the condition of the sod, such as its thickness, its age, the type of soil, whether it is wet or dry, and even depending on the variety of grass. In addition the characteristics of the sod can vary greatly from one point in a roll of sod to another, e.g. if the roll has been left sitting in which case the top of the roll tends to dry out and the bottom of the roll tends to become more moist. The sod also tends to stretch unevenly when it is being laid, forming unsightly buckles which must be removed, and it may frequently break, interrupting the sod laying operation.
In addition the locations in which sod must be laid are frequently restricted as to access and limited in space. Further, the sod must commonly be laid up against walls and fences. Therefore a successful sod laying machine should be relatively small and maneuverable and able to lay the fragile sod accurately while reducing the likelihood of breaks and buckles in the sod.